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Volume 15, Issue 4
Displaying 1-9 of 9 articles from this issue
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Part 1. Diffusion of smoke from a continuous fixed source on the ground surfaceE. INOUE1960 Volume 15 Issue 4 Pages 123-129
Published: March 25, 1960
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe diffusion phenomena of smoke emitted from a continuous point source in the atmospheric surface layer are dealt with separately in the vertical and in the lateral wind directions. For the lateral diffusion the Taylor method making use of Lagrangian correlation function is applied and for the vertical diffusion the Monin method making use of the relation between the vertical turbulent velocity components and the mean horizontal wind velocity is applied. The diffusion width ‹Y2›1/2 and the diffusion height ‹Z2›1/2 of smoke from the ground source are calculated theoretically under characteristic thermal conditions and the downwind distributions of maximum concentration χp are calculated theoretically too as follows being x the downwind distance from the source:
(a) Extremely unstable:
‹Y2›1/2_??_x,
‹Z2›1/2_??_x1.5,
χp_??_x-2.5.}
(b) Neutral:
‹Y2›1/2_??_x,
‹Z2›1/2_??_x0.8,
χp_??_x-1.8.}
(c) Extremely stable:
χp_??_x-1.5--1.0}
These results are shown in good agreement with Cramer's (1957) empirical relations obtained at the Project Prairie Grass.View full abstractDownload PDF (992K) -
Winderosion-prevention by catch ditch of flying soilS. TANAKA, H. SANO, T. TANIZAWA, S. KAKINUMA1960 Volume 15 Issue 4 Pages 130-132
Published: March 25, 1960
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSWinderosion damages frequently such bare-cultivated land all over as sweet-potato-field digged up. We checked up for degree of the erosion in an open land and in four partitions whose ditch-width are 120cm, 180cm, 240cm, and 300cm, in each.
Most of flying soil, saltation as it is, drifts under 50cm, over the ground, while 10% of it moves in the shape of surface creep. Catch ditch of flying soil is intended for the interception of all the surface creep and the greater bulk of saltation there into the veryditch. Though its capacity is dependent on the erosive degree how the ground is blessed with, we found that 50% of saltation or so and the whole surface creep can be trapped.
Each ditch with shorter interval brings greater efficacy, but we are afraid unfit pile-up of soil may let bring severe winderosion, so that adequate ditch should be of two meter intervals. An inverted trapezoid, V-concave form, is sure to be better than any other, for a ditch with vertical section, U-form, is fragile and soon filled up with soil.View full abstractDownload PDF (429K) -
Results of Preliminary Observation in Matsukawa-machi, Nagano PrefectureM. YOSHINO, T. NISHIZAWA1960 Volume 15 Issue 4 Pages 133-138
Published: March 25, 1960
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSA preliminary study on the cold air drainage and the local distribution of frost was made in Matsukawa-machi, Shimoina, Nagano Prefecture on March 31 to April 5, 1958. Analyzing thermograph records observed at eight stations in the area, movements of the cold air were discussed in detail. Then, an example of up and down motion of inversion layer at night of April 4-5 was given in relation to the cold air drainage. A distribution map of air temperature measured by mobile observation in the most frosty part of the area showed marked localization. As conclusion, it was confirmed that the air came from the upper area of the river course, but they formed colder air masses at the upper parts of the studying area, and then flew down as the cold air drainage under the influence of micro-topography.View full abstractDownload PDF (1026K) -
E. MARUYAMA, M. TAKASUNA1960 Volume 15 Issue 4 Pages 139-142
Published: March 25, 1960
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe report on the possibility of computing the amount of evaporation from the soil surface using the vertical moisture gradient measured in the soil was made in the previous experimental study (Suzuki, S and Maruyama, E. 1957).
We measvred the evaporation from the surface of loam-and clay-soil by the method mentioned in the previous report, in the vast plain field attached to the Aero-Meteorological Observatory, Tateno in Ibaragi Prefecture, and at the same time in order to check the actual amount of evaporation from the same soil, we weighted hourly a steel cylinder vessel containing loam and clay-soil in it imbeded in the earth of the same soil structure.
Those two methods led to the vary same values. At the same time the values were found coincided with the ones estimated from the vertical gradient of vapour density in the atmosphere near the ground which was observed by another member of our observation group in the neighbourhood of the Observatory.
It was of much interest that the values calculated by means of Thornthwaite-Holtzman's formula reffered to the vertical distributions of wind-velocity, relative humidity and temperature, which were observed by the same group and in the same place, were found considerably different from ours.View full abstractDownload PDF (555K) -
Y. NAKAGAWA1960 Volume 15 Issue 4 Pages 143-146
Published: March 25, 1960
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSIn order to research the radiation balance in the paddy field and the relation between water temperature in the percolating paddy field to percolation, the author carried out the observations of the radiation, water temperature, percolation in August 1958 at Nyuzen, Toyama Pref.
The radiations were measured by using Beckman's net radiometer, hemispherical radiometer and Golzinsky solarimeter.
The results obtained are as follows;
(1) The radiation balance in the cultivated field is shown as following formula,
S=RS(1-α)+(R↓-R↑)
where S, RS, α, R↓, R↑ refer to the net radiation, short wave radiation, albedo, long wave radiation from upward and that from downward, respectively.
The results measured in the paddy field was shown in Fig. 2.
(2) The relations between rising effect of temperature in the percolating paddy field to percolation was found theoretically as shown in formula (16),
θwp-θ0=(θw0)exp(v/-(LρaDdqs/dθ+cpρaD)),
where θwp, θw0, v, L, ρa D, cp, q refer to the average water temperature in the percolating paddy field, average water temperature in the no percolating field, irrigating watea temperature, percolation (c. c. per min), latent heat (590 cal), density of air, diffusion coefficient (39cm per min), specific heat of air and specific humidity, respectively.View full abstractDownload PDF (481K) -
Y. KODANI, H. KIMURA1960 Volume 15 Issue 4 Pages 147-150
Published: March 25, 1960
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSUsing the sand dune soil and red soil as soil samples, and Bouyoucos plaster of paris block and Nylon unit as absorption units, authors studied on; relationship of soil moisture content and electrical resistance of absorption units, calibration repeating drying and wetting processes, the time requird soil moisture and absorption units arrive at the state of equilibrium, and applicability of absorption units for the soils.
The results are summarized as follows.
1) Applying on sand dune soil and red soil, relation-curves between the soil moisture and block resis Lance are shown in Fig. 1 and in Fig. 2. It is recognized that Nylon unit can be used for both soils, but plaster of paris block should be used only for red soil.
2) The relation curves between soil moisture of sand dune soil and Nylon unit resistance, repeating drying and wetting processes for five times, is shown in Fig. 3. It is seen that the relations are not certain in earlier processes but are fairly constant in the forth or fifth processes.
3) As the curves are different considerably from each other units, as shown in Fig. 4. it may be important to calibrate absorption unit before using in the field.
4) The time required to present real reading in saturated soil are 4-6 hours for plaster of paris block and 15-25 minutes for Nylon unit.View full abstractDownload PDF (568K) -
R. YAMAMOTO1960 Volume 15 Issue 4 Pages 151-160
Published: March 25, 1960
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe effects of an obstacle before or behind the hedge on the windbreak effect of the hedge were investigated by making indoor experiments using a wind tunnel and an air blowing installation with two electric fans, and also by making outdoor experiments in an open land.
The measurement of wind velocity was made with a pitot tube, a hot wire anemometer and Biram's anemometer.
The results obtained were as follows:
1. When there is an obstacle before the hedge, the windbreak effect of the hedge is lesser than when there is none.
2. As regards the distance betweenthe hedge and the obstacle, the effect of the obstacle on the windbreak effect of the hedge is the largest when it is 2 or 3 times of the hedge height. But it seems to very more or less with shape of the obstacle and the vertical distribution of wind velocity.
3. The obstacle before hedge which reduces the windbreak effect of the hedge need not be a board fence of the like. A lattice fence or an irregular-shaped fence will do for the purpose, too.
4. The above-mentioned facts that were observed in the indoor experiments could mostly be seen in the outdoor experiment, too.
5. The mechanism that the obstacle before the hedge reduces the windbreak effect of the hedge is that the total resistance of the obstacle and hedge against the wind flow is lesser than the resistance of the hedge alone.
6. When another hedge is located near the hedge, the zone of weak wind behind the hedge increases in case the both are of lower closeness but decreases in case they are of higher closeness.
7. When the windbreak with a great deal of opening in the lower part is helped with a supplementary one, a careful consideration should be given to the distance betweed them. Because the larger is the distance, the less is the windbreak effect of the former. Besides, its capacity for covering the opening of the former is reduced.
8. The effect of the obstacle before the hedge upon the latter's windbreak effect is more remarkable when the hedge is used for the purpose of deflecting wind direction in a hilly land than when it is used as the windbreak in a level land,View full abstractDownload PDF (3065K) -
M. YOSHINO1960 Volume 15 Issue 4 Pages 161-165
Published: March 25, 1960
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (758K) -
1960 Volume 15 Issue 4 Pages 165
Published: March 25, 1960
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (121K)
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